Sensitization of Gd3+ and the dynamics of quantum splitting in GdF3:Pr,Eu

Efforts are reported to sensitize the Gd3+ excitation with Pr3+ for application to quantum cutting in GdF3 doped with Eu3+ and Pr3+. Excitation and emission spectra are reported for several samples with different concentrations of Eu3+ and Pr3+ at room temperature. In addition, time-resolved measurements are performed to obtain the dynamics of the various excited states of Gd3+. Strong enhancement of the D-5(0) Eu3+ emission is observed for excitation of (6)G of Gd3+ relative to that for other Gd3+-excited states as expected for quantum cutting. While some enhancement of the J = 0 Eu3+ emission is also observed for excitation into the Pr3+ 4f5d states, the maximum quantum yield is disappointing, failing far below the desired goal of 2. The time-resolved studies indicate that one reason for the ineffective quantum cutting is that the Pr3+ -> Gd3+ energy transfer occurs predominantly to the 6I state of Gd3+. Results on the I-6 -> P-6 relaxation and the Gd3+(P-6(7/2)) -> Eu3+ energy transfer are described. (c) 2006 Elsevier B.V. All rights reserved.